The invention relates to a device for cleaning liquids, in particular edible oils, by means of a filter in a filter housing, the filter being connected downstream of a pump, and a motor for driving the pump, which has a rotor having a rotor disc with vanes in an immersion housing being provided in a housing, the housing, immersion housing and filter housing together forming a unit which can be at least partially introduced into the liquid which is to be cleaned and removed therefrom.
In both the domestic and the industrial sector, there are numerous liquids which have to be cleaned. These include, for example, coolant or lubricant baths in machine tools, and edible oils, for example from fryers. These are only a few examples, but the invention is intended to apply to all possible liquids which are to be cleaned.
In general, the liquid is from time to time removed from a storage tank and passed to a device for cleaning this liquid. From there, the liquid is then returned to the storage tank. Often, however, only the surface of the liquid is sucked up, so that the light, floating substances are removed. The heavier particles of impurities are then removed-at the bottom from time to time after they have settled.
The present invention relates in particular to oils originating from fryers. It is usual for these oils also to be sucked up, filtered and pumped back into the fryer. In this case, a cleaning powder, for example kieselguhr, is also scattered into the medium prior to filtration.
The cleaning of oils and fats is important because in theory, given complete cleaning, the oils and fats can be constantly reused. Given a price of approximately DM 2.00 per liter of frying oil and a reduction in service life by five to ten times, a filtration system can pay for itself within a few months.
Devices of the type described above are known, for example, from U.S. Pat. No. 3,356,218, U.S. Pat. No. 3,447,685 and in particular from U.S. Pat. No. 3,415,181. In these devices, the oil which is to be cleaned is sucked off the bottom by means of a pump and is laterally discharged from the pump into a riser. Downstream of this riser there is a filter, through which the liquid which is to be cleaned passes before then being returned to the bath via a return line.
The present invention is based on the object of providing a device which allows the liquid to be cleaned significantly more easily, more quickly and possibly without the addition of cleaning powder.